1. Field of the Invention
The present invention relates to a process cartridge and an electrophotographic image forming apparatus in which the process cartridge is detachably mountable.
The electrophotographic image forming apparatus forms an image on a recording medium utilizing an electrophotographic image forming process, and includes, for example, an electrophotographic copying apparatus, an electrophotographic printer (such as an LED printer, a laser beam printer etc.), an electrophotographic facsimile apparatus and an electrophotographic word processor.
Also, the process cartridge integrally includes charging means, developing means or cleaning means and an electrophotographic photosensitive member as a cartridge, which is rendered detachably mountable in a main body of an electrophotographic image forming apparatus. Also, the process cartridge integrally includes at least one of the charging means, developing means and cleaning means with an electrophotographic photosensitive member as a cartridge, which is rendered detachably mountable in a main body of an electrophotographic image forming apparatus. Furthermore the process cartridge integrally includes at least the developing means and the electrophotographic photosensitive member as a cartridge, which is rendered detachably mountable in a main body of an electrophotographic image forming apparatus.
2. Related Background Art
The recent electrophotographic image forming apparatus for forming an image on the recording medium utilizing an electrophotographic image forming process often employs the process cartridge system in which the electrophotographic photosensitive member and process means for acting thereon are integrally made into a cartridge that is detachably mountable in the main body of the image forming apparatus. Such process cartridge system can significantly improve operability since the maintenance of the apparatus need not be executed by a service personnel but can be achieved by the user himself. For this reason, the process cartridge system is widely employed in the image forming apparatus.
In the electrophotographic image forming apparatus in which the process cartridge is detachably mountable for forming an image on the recording medium, the photosensitive drum provided in the process cartridge is given a driving force from the driving source of the main body of the apparatus through a driving force transmitting member. As an example, an output gear constituting the driving force transmitting member in the main body of the image forming apparatus meshes with a gear (called drum gear) provided on the photosensitive drum. Also, for driving the transfer roller, a transfer roller gear concentric with the transfer roller meshes with a gear fixed to the photosensitive drum. In such configuration, the drum gear is a helical gear while the transfer roller gear is a spur gear.